Electric switch gear



Oct. 13, 193 THUMIM 2,057,546

ELECTRIC SWITCH GEAR Filed Nov. 6, 1935 lTl-vencor'f COT"\ Thumim,

b g Attorney.

Patented Oct. 13, 1936 PATENT oFFieE ELECTRIC SWITCH GEAR Carl Thumim, Yeadon,

Electric Company,

Pa., assignor to General a corporation of New York V Application November 6, 1935, Serial No. 48,512

5 Claims.

My invention relates to electric switch gear, more particularly to operating mechanism for electric circuit breakers, and has for its principal object the provision of an improved and simplified manual operating mechanism which is compact and rugged in construction and which is adapted effectively to apply a comparatively small manual operating'force for closing the breaker.

In previous types of manual operating mechanisms for electric circuit breakers, the usual manual arrangement includes a lever which is pulled down by the operator for closing the breaker. In such a case, due to space limitations, the movement of the lever is limited to an arc of about 180 degrees so that a considerable force may have to be applied, particularly in the case of high resistance peaks in the closing characteristics of the breaker. Lengthening of the manual lever for increasing the mechanical advantage may be in many cases objectionable, particularly where space is an important factor.

In accordance with my invention, this problem is overcome by utilizing a cam in unitary combination with an operating lever coacting with the thrust transmitting structure of the circuit breaker arranged so that the manual operating force can be applied through an arc of approximately 300 degrees; and more particularly, the arrangement is such that the arc through which the manual operating force is applied to the cam is generally in a plane parallel to the front of the circuit breaker so that, notwithstanding comparatively large resistance of the breaker mechanism to closing; a suificiently large operating force may be readily applied through the cam without appreciable obstruction of the space in front of the circuit breaker. v

My invention will be more fully set forth in the following description referring to the accompanying drawing, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Referring to the drawing, Fig. 1 is an elevational View, partly in section, of an electric circuit breaker having a manual operating mechanism embodying my invention'and Fig. 2 is an end View of part of the manual operating mechanism shown in Fig. 1. 1

Fig. 1 illustrates a manual operating mechanism I for operating a heavy duty electric circuit breaker, such as a conventional oil circuit breaker 2. The circuit breaker in the present instance comprises an oil-containing tank 3 in which are disposed the relatively movable contacts (not shown), the movable contacts being carried by a vertically guided lift rod 4 and the coacting stationary contacts being connected to the lower ends of the lead-in conductor bushings 5 which extend through the cover structure 3 of the cir- 5 cuit breaker.

The circuit breaker is operated by vertical movement of the lift rod 4, upward movement to the position shown closing the breaker and lowering of the rod opening the breaker. Suitable operating and thrust transmitting structure connected to the lift rod 4 is provided for transmitting an exterior operating force to the movable contact structure. In the present case the rod 4 is connected at 6 to a so-called straight-line linkage mechanism 1 which includes a lever 8 pivoted at 9 with respect to the cover structure 3'. The lever 8 is in turn suitably connected to a bellcrank III which is pivotally mounted to the cover structure at II and extends through said cover for connection at I 2 to a trip-free operating linkage.

The specific trip-free linkage illustrated forms no part of the present invention and comprises a floating lever l3 connected at one end through a link M to the bellcrank H] at I2 and at the other end to a link l5 forming a toggle which is in turn connected at the knee joint 13' to a tripping toggle IS. The tripping toggle is in turn controlled by a pivoted latch I! which is released by a tripping solenoid IS. The linkage above described is held in thrust transmitting position for maintaining the breaker closed by a pivoted prop I 9 which is engaged by a pin 20 carried by the floating lever I3.

When the thrust transmitting linkage is to be released for causing opening of the breaker, the tripping solenoid I8 is energized so as to lift the latch I 7 and release the toggle Hi. The toggle 16 immediately buckles under the breaker reacting force transmitted by the bellcrank l0 and floating lever l3, so that the floating lever is no longer restrained and slides away from the prop l 9. This permits the bellcrank H) to rotate freely in a clockwise direction coincident with lowering of the llftrod 4. When the linkage reaches a position of rest, the tripping toggle l6 automatically resets with respect to latch I! so that an operating force applied upwardly to the roller 20 of the floating lever causes rotation of the fioating lever in a clockwise direction about the restrained toggle pin I 3 causing'counterclockwise rotation of the crank l0 and closing of the breaker.

The operating force acting upwardly on the a being engaged by the roller 20 is applied by means of a plunger 2| which is guided for vertical movement through the base plate 22 which forms at the front of the breaker a part of the cover structure 3' and supports a pair of vertically spaced plates 23 between which the trip-free linkage is mounted. The plunger 2| is biased downwards by means of a spring 2| and is connected at its lower end at 23 to one end of a lever 25. The lever 25 is in turn pivotally mounted at 26 on a lug 21 secured to the lower face of a mounting bracket or frame 28. The bracket which is detachably secured, as by bolts 29, to the lower side of the base plate 22 is provided with a cylindrical portion 30 which extends through an aperture in the base plate 22 so as to position the frame 28 and forms a retaining seat for the spring 2| acting on the plunger 2|. As illustrated, the plunger 2| is slidably guided through the upper end of the member 30.

The other end of the lever 25, referring also to Fig. 2, is provided with a roller 3| which is mounted on a pin 32 extending generally parallel to the longitudinal axis of the lever 25. The pin 32 is suitably mounted in a U-shaped bearing member 33 carried at the end of the lever 25.

A cam 34, rotatably mounted in a bearing 35 forming a part of the bracket structure 28, is disposed generally in a plane parallel to the front of the breaker and transversely of the longitudinal axis of the lever 25 so as to engage the roller 3|. The cam 34 is rotated by means of a manual operating handle 36 which takes up comparatively little space at the front of the breaker, particularly when in use.

In the position shown, the mechanism has just completed the closing operation, the roller 3| high point of the cam 34. In this position, the prop l9 holds the trip-free linkage in a restraining position independently of the cam-operated lever 25, so that the handle 36 is free to swing down to a vertical position. The spring 2| thereupon rotates the lever 25 counterclockwise, withdrawing roller 20 and causing the roller 3| to engage the low point of the cam 34. In this position the manual operating means is in readiness for operation when the trip-free linkage |3, |5, etc. collapses and the roller 20 again rests on the upper end of plunger 2|. The operating face of the cam can not only be designed to compensate for high resistance peaks during the breaker closing, but the manual force can be applied throughout an arc of approximately 300 degrees or more so that a high mechanical advantage is obtained notwithstanding the compactness of the mecha- 'nism.

The manual operating mechanism likewise provides for trip-free operation since at any time during the closing operation the tripping toggle it may be released so that the breaker reacting force causes the roller 2|] to slide off the end of the plunger 2|.

The manual operating mechanism as a portable detachable unit may be interchangeably used with solenoid mechanism which can readily be secured beneath the base plate 22.

It should be understood that my invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one the plunger 2| from theskilled in the art without departing from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In electric switch gear including an electric circuit breaker having a tank and an enclosing cover therefor and a thrust-transmitting linkage for closing said breaker, manual operating means coacting with said linkage comprising a supporting frame mounted on said cover, a lever pivotally mounted on said frame and operatively connected to said linkage, and a manually operated cam rotatably mounted in said frame operatively connected to said lever.

2. In electric switch gear including an electric circuit breaker having an enclosing cover, said cover having a lateral extension, and a thrusttransmitting linkage for closing said breaker, a manual operating unit coacting with said linkage comprising a supporting frame detachably secured to said lateral extension, a lever pivotally mounted.

on said frame and disengageably related to said linkage, and a manually operated cam rotatably mounted in said frame and operatively connected to said lever.

3. In electric switch gear including an electric circuit breaker and a thrust-transmitting linkage for closing said reaker, manual operating means coacting with said linkage comprising a lever pivotally mounted with respect to said breaker, a plunger connected to one part of said lever and disengageably related to said linkage, a roller carried by another part of said lever, the axis of rotation of said roller being generally parallel to the longitudinal axis of said lever, and a manually operated cam rotatably mounted with respect to said breaker coacting with said roller.

4. In electric switch gear including an electric circuit breaker, a thrust-transmitting linkage for closing said breaker and a base plate therefor, a manual operating unit coacting with said linkage comprising a supporting frame detachably secured to the lower side of said base plate, a lever pivotally mounted on said frame, a member connected to one end of said lever for coaction with said linkage through said base plate, and a manually operated cam rotatably mounted in said frame, said cam being rotatable in a plane generally parallel to the front of said breaker.

5. In electric switch gear including an electric circuit breaker, a thrust-transmitting linkage for closing said breaker and a base plate therefor, a manual operating unit coacting with said linkage comprising a supporting frame detachably secured to the lower side of said base plate, a lever pivotally mounted intermediate its ends on said frame, a plunger connected to one end of said lever and extending through said base plate for coaction with said linkage, a cylindrical member forming a part of said frame extending through said base plate for guiding said plunger and for positioning said unit, a spring seated in said cylindrical member normally biasing said plunger away from said linkage, a cam rotatably mounted in said frame, the axis of rotation of said cam being generally in a plane with the longitudinal axis of rotation of said lever, and a roller carried by said lever for coaction with said cam, the axis of rotation of said roller being generally in a plane with the axis of rotation of said cam.

CARL THUMIM. 

